Bidoof

I'm going to buy a flashcart. But i got some questions. Which flashcart would you recommend? I don't have that much experience on flashcart, but from what i've understand r4 is good? Is it easy to get Pokémon you create in Pokégen to a game? Do you have to use a Pokémon-rom or can you get the Pokémon you create in Pokegen onto a legit, real copy of say Pokemon White? And finally, would a r4 card work just as fine on a 3DS? Thanks!